56 A1120/40 - Electronic Polyphase Meter
© Elster Metering Limited - M181 001 2G - 5/2010
APPENDIX A - Checking kWh and kvarh Registration Accuracy
WARNING
Only trained and competent personnel, familiar with meter test procedures should carry out the
following operation.
A1 Introduction
Various methods of checking the accuracy of registration of the A1120/40 meter are available.
Methods using the LED test indicators and Register advances are described below.
A2 Checking Meter Accuracy Using the LED Test Indicator
The LED test indicators are configured at manufacture to pulse for import kWh and import kvarh
(import only meter) or pulse for import plus export kWh and kvarh (import/export or power flow
insensitive meters).
A2.1 Comparing the number of LED pulses with substandard meter register advance
What you will need
Suitable test equipment with a sensor to detect LED pulses
A suitable substandard meter (set to the same system configuration as the meter under test)
A counter for counting the number of LED pulses
Checking registration
In orde
r to achieve a rep
eatability of 0.1% the test time at any load needs to be a minimum of 60
seconds.
1. Connect the test equipment and a suitable load to the meter, then power up the meter
2. The right hand Test LED pulses for kWh
3. Run the test for a suitable duration and check the amount the substandard has advanced and
the number of pulses detected
Calculate the registration by dividing the number of pulses by the meter constant.
e.g. 994
(LED count) = 0.994 kWh advance.
1000 (meter constant)
Compare this kWh advance with the amount the substandard has advanced.
Repeat for kvarh using left hand Test LED.
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